This invention relates to the field of voltage regulation and more particularly to the prevention of both overload damage and unnecessary power supply shut down.
Since a continuous overload as well as a short circuit can destroy a voltage regulator, these systems have been developed to avoid such damage. Typically, these systems use one of two main approaches, current limiting or regulative cut off, with some means of current limiting being the most common. However, the concept of limiting as a solution has a serious flaw in that the system must limit at some margin above the desired level. Thus, unless all components have large safety factors, some portion of the regulator will almost certainly be damaged if a moderate overload condition continues for an extended period. The failure of one component, of course, almost inevitably leads to other failures.
To avoid this possibility, various systems have been devised to cut off supply when overload condition is sensed. This approach, however, usually produces annoyance from unnecessary shut downs triggered by momentary overloads.